A flash memory, in particular, a NAND flash memory begins to be applied to various fields such as a memory card, and an SSD (solid state drive) as a storage memory. In these fields, when a flash memory system is configured, one of important problems is to increase a data writing speed.
Incidentally, an interleave operation is known as a technology for improving a data transfer speed. Accordingly, when the technology is applied to the flash memory, there is a possibility that the problem of increasing the data writing speed can be solved.
However, the flash memory has such an inherent data writing system that the flash memory cannot overwrite data to a memory cell (physical page), that is, when the flash memory overwrites data, the flash memory must withdraw an old block and rewrite the data to a new block.
Accordingly, the increase of the data writing speed is realized by developing an interleave operation that matches the data writing system of the flash memory.